Associations between weekly maternal exposure to ambient particulate matter and congenital heart disease

Background The association between maternal exposure to air pollution and congenital heart diseases (CHDs) has garnered increasing attention. However, investigations into critical weekly specific exposure windows for CHDs remain limited. This study evaluated the relationship between maternal ambient particulate matter exposure throughout the entire pregnancy period and the risk of CHDs, as well as explored critical weekly specific exposure windows. Method Based on the Jiangsu Maternal and Child Health Monitoring Manual and the Environmental Health Department of Suzhou CDC, 19,914 pregnant women with complete hospital delivery records between 2021 and 2023 were included, and the concentration data for five air pollutants (PM 10 , PM 2.5 , NO 2 , CO, and SO 2 ) in Suzhou City from 2020 to 2023 were obtained in this study. Distributed lag models (DLMs) incorporated in Cox proportional-hazards models were applied to assess the exposure-lag-response relationship between the weekly average exposure levels during pregnancy and the risk of CHDs, identifying the refined exposure windows. Results A 10 μg/m 3 increase in maternal exposure to PM 10 was positively associated with CHDs during gestational weeks 5–12 and weeks 18–22 ( p < 0.05). The strongest association was observed in gestational weeks 5 and 6 (HR, 1.010; 95% CI, 1.000–1.020; HR, 1.010; 95% CI, 1.002–1.017). The association between maternal exposure to PM 2.5 and the risk of CHDs was not observed during all gestational weeks. Conclusion Our study results demonstrate that exposure to high concentrations of PM 10 increases the risk of CHDs, with susceptible exposure windows identified as gestational weeks 5–12 and weeks 18–22. Our study provides further evidence supporting the association between maternal exposure to ambient particulate matter and CHDs while also identifying critical windows. However, further studies are required to confirm these findings.